<template>
  <div class="home-page">

    <div class="banner">
      <div class="container">
        <h1 class="logo-font">conduit</h1>
        <p>A place to share your knowledge.</p>
      </div>
    </div>

    <div class="container page">
      <div class="row">

        <div class="col-md-9">
          <div class="feed-toggle">
            <ul class="nav nav-pills outline-active">
              <li class="nav-item" v-if="user">
                <nuxt-link class="nav-link" :class="{ active: tab === 'your_feed'}" :to="{
                  name: 'home',
                  query: {
                    tab: 'your_feed'
                  }
                }" exact>Your Feed</nuxt-link>
              </li>
              <li class="nav-item">
                <nuxt-link class="nav-link" :class="{ active: tab === 'global_feed'}" :to="{
                  name: 'home',
                  query: {
                    tab: 'global_feed'
                  }
                }" exact>Global Feed</nuxt-link>
              </li>
              <li class="nav-item" v-if="tag">
                <nuxt-link class="nav-link" :class="{ active: tab === 'tag'}" :to="{
                  name: 'home',
                  query: {
                    tab: 'tag',
                    tag: tag
                  }
                }" exact># {{ tag }}</nuxt-link>
              </li>
            </ul>
          </div>

          <div class="article-preview"
            v-for="article in articles" :key="article.slug"
          >
            <div class="article-meta">
              <nuxt-link :to="{
                name: 'profile',
                params: {
                  username: article.author.username
                }
              }"><img :src="article.author.image" /></nuxt-link>
              <div class="info">
                  <nuxt-link class="author" :to="{
                    name: 'profile',
                    params: {
                      username: article.author.username
                    }
                  }">{{ article.author.username }}</nuxt-link>
                <span class="date">{{ article.createdAt | date('MMM DD, YYYY') }}</span>
              </div>
              <button class="btn btn-outline-primary btn-sm pull-xs-right" :disabled="article.favoriteDisabled"
                :class="{ active: article.favorited }" @click="onFavorite(article)">
                <i class="ion-heart"></i> {{ article.favoritesCount}}
              </button>
            </div>
            <nuxt-link :to="{
              name: 'article',
              params: {
                slug: article.slug
              }
            }" class="preview-link">
              <h1>{{ article.title }}</h1>
              <p>{{ article.description }}</p>
              <span>Read more...</span>
            </nuxt-link>
          </div>

          <!-- 分页列表 -->
          <nav>
            <ul class="pagination">
              <li class="page-item" v-for="item in totalPage" 
                :key="item" :class="{ active: item == page }"
              >
                <nuxt-link class="page-link " :to="{
                  name: 'home',
                  query: {
                    page: item,
                    tag: $route.query.tag,
                    tab: tab
                  }
                }">{{ item }}</nuxt-link>
              </li>
            </ul>
          </nav>
        </div>

        <div class="col-md-3">
          <div class="sidebar">
            <p>Popular Tags</p>

            <div class="tag-list">
              <nuxt-link :to="{
                name: 'home',
                query: {
                  tag: item,
                  tab: 'tag'
                }
              }" class="tag-pill tag-default"
                v-for="item in tags" :key="item"
              >{{ item }}</nuxt-link>
            </div>
          </div>
        </div>

      </div>
    </div>

  </div>
</template>

<script>
import { getArticles, getYourArticles, addFavorite, deleteFavorite } from '@/api/article'
import { getTags } from '@/api/tag'
import { mapState } from 'vuex'

export default {
  name: 'HomeIndex',
  watchQuery: ['page', 'tag', 'tab'],
  async asyncData({ query }) {
    const page = Number.parseInt(query.page || 1)
    const limit = Number.parseInt(query.limit || 6)
    const tab = query.tab || 'your_feed'
    const tag = query.tag
    const loadArticles = tab !== 'your_feed' ? getArticles : getYourArticles
    const [ articleRes, tagRes] = await Promise.all([
      loadArticles({
        limit,
        offset: (page - 1) * limit,
        tag
      }),
      getTags()
    ])
    const { articles, articlesCount } = articleRes.data
    const { tags } = tagRes.data
    articles.forEach(item => item.favoriteDisabled = false)
    return {
      articles,
      articlesCount,
      limit,
      page,
      tags, // 标签列表
      tab, // 选项卡
      tag // 数据标签
    }
  },
  computed: {
    ...mapState(['user']),
    totalPage () {
      return Math.ceil(this.articlesCount / this.limit)
    }
  },
  methods: {
    async onFavorite(article) {
      article.favoriteDisabled = true
      if(article.favorited) {
        // 取消点赞
        await deleteFavorite(article.slug)
        article.favorited = false
        article.favoritesCount -= 1
      } else {
        await addFavorite(article.slug)
        article.favorited = true
        article.favoritesCount += 1
      }
      article.favoriteDisabled = false
    }
  }
}
</script>

<style>

</style>